/*
 * Copyright (c) 2015-2017, ARM Limited and Contributors. All rights reserved.
 *
 * SPDX-License-Identifier: BSD-3-Clause
 */

#include <arch_helpers.h>
#include <assert.h>
#include <bl_common.h>
#include <context_mgmt.h>
#include <string.h>
#include "tlkd_private.h"

#define AT_MASK        3

/*******************************************************************************
 * This function helps the SP to translate NS/S virtual addresses.
 ******************************************************************************/
uint64_t tlkd_va_translate(uintptr_t va, int type)
{
    uint64_t pa;

    if (type & TLK_TRANSLATE_NS_VADDR) {

        /* save secure context */
        cm_el1_sysregs_context_save(SECURE);

        /* restore non-secure context */
        cm_el1_sysregs_context_restore(NON_SECURE);

        /* switch NS bit to start using 64-bit, non-secure mappings */
        write_scr(cm_get_scr_el3(NON_SECURE));
        isb();
    }

    int at = type & AT_MASK;
    switch (at) {
    case 0:
        ats12e1r(va);
        break;
    case 1:
        ats12e1w(va);
        break;
    case 2:
        ats12e0r(va);
        break;
    case 3:
        ats12e0w(va);
        break;
    default:
        assert(0);
    }

    /* get the (NS/S) physical address */
    isb();
    pa = read_par_el1();

    /* Restore secure state */
    if (type & TLK_TRANSLATE_NS_VADDR) {

        /* restore secure context */
        cm_el1_sysregs_context_restore(SECURE);

        /* switch NS bit to start using 32-bit, secure mappings */
        write_scr(cm_get_scr_el3(SECURE));
        isb();
    }

    return pa;
}

/*******************************************************************************
 * Given a secure payload entrypoint, register width, cpu id & pointer to a
 * context data structure, this function will create a secure context ready for
 * programming an entry into the secure payload.
 ******************************************************************************/
void tlkd_init_tlk_ep_state(struct entry_point_info *tlk_entry_point,
                uint32_t rw,
                uint64_t pc,
                tlk_context_t *tlk_ctx)
{
    uint32_t ep_attr, spsr;

    /* Passing a NULL context is a critical programming error */
    assert(tlk_ctx);
    assert(tlk_entry_point);
    assert(pc);

    /* Associate this context with the cpu specified */
    tlk_ctx->mpidr = read_mpidr_el1();
    clr_yield_smc_active_flag(tlk_ctx->state);
    cm_set_context(&tlk_ctx->cpu_ctx, SECURE);

    if (rw == SP_AARCH64)
        spsr = SPSR_64(MODE_EL1, MODE_SP_ELX, DISABLE_ALL_EXCEPTIONS);
    else
        spsr = SPSR_MODE32(MODE32_svc,
                   SPSR_T_ARM,
                   read_sctlr_el3() & SCTLR_EE_BIT,
                   DISABLE_ALL_EXCEPTIONS);

    /* initialise an entrypoint to set up the CPU context */
    ep_attr = SECURE | EP_ST_ENABLE;
    if (read_sctlr_el3() & SCTLR_EE_BIT)
        ep_attr |= EP_EE_BIG;
    SET_PARAM_HEAD(tlk_entry_point, PARAM_EP, VERSION_1, ep_attr);

    tlk_entry_point->pc = pc;
    tlk_entry_point->spsr = spsr;
}

/*******************************************************************************
 * This function takes a TLK context pointer and:
 * 1. Applies the S-EL1 system register context from tlk_ctx->cpu_ctx.
 * 2. Saves the current C runtime state (callee saved registers) on the stack
 *    frame and saves a reference to this state.
 * 3. Calls el3_exit() so that the EL3 system and general purpose registers
 *    from the tlk_ctx->cpu_ctx are used to enter the secure payload image.
 ******************************************************************************/
uint64_t tlkd_synchronous_sp_entry(tlk_context_t *tlk_ctx)
{
    uint64_t rc;

    /* Passing a NULL context is a critical programming error */
    assert(tlk_ctx);
    assert(tlk_ctx->c_rt_ctx == 0);

    /* Apply the Secure EL1 system register context and switch to it */
    assert(cm_get_context(SECURE) == &tlk_ctx->cpu_ctx);
    cm_el1_sysregs_context_restore(SECURE);
    cm_set_next_eret_context(SECURE);

    rc = tlkd_enter_sp(&tlk_ctx->c_rt_ctx);
#if DEBUG
    tlk_ctx->c_rt_ctx = 0;
#endif

    return rc;
}

/*******************************************************************************
 * This function takes a TLK context pointer and:
 * 1. Saves the S-EL1 system register context to tlk_ctx->cpu_ctx.
 * 2. Restores the current C runtime state (callee saved registers) from the
 *    stack frame using reference to this state saved in tlkd_enter_sp().
 * 3. It does not need to save any general purpose or EL3 system register state
 *    as the generic smc entry routine should have saved those.
 ******************************************************************************/
void tlkd_synchronous_sp_exit(tlk_context_t *tlk_ctx, uint64_t ret)
{
    /* Passing a NULL context is a critical programming error */
    assert(tlk_ctx);

    /* Save the Secure EL1 system register context */
    assert(cm_get_context(SECURE) == &tlk_ctx->cpu_ctx);
    cm_el1_sysregs_context_save(SECURE);

    assert(tlk_ctx->c_rt_ctx != 0);
    tlkd_exit_sp(tlk_ctx->c_rt_ctx, ret);

    /* Should never reach here */
    assert(0);
}
